1. Field of the Invention
This invention relates generally to the field of thrust bearings for turbocharger rotor groups and, more particularly, to a double sided 360xc2x0 thrust bearing having separable elements with a plurality of bearing pads on a first side and one elevated segment with at least one bearing pad on the opposite side interlinking with an open segment on the opposite element to form a complete double sided bearing.
2. Description of the Related Art
Turbochargers which have higher thrust loads, such as those for large diesel engine applications, typically employ a dedicated thrust bearing to react the thrust forces. For ease of assembly, typical bearings are horseshoe shaped to be received over the rotor shaft of the turbocharger to engage a thrust collar mounted on the shaft. The thrust collar has a circular channel which receives the thrust bearing and provides the reaction surface for the bearing pads machined in the surface of the thrust bearing. In many cases, the thrust bearing is double sided, having bearing pads on each side to accommodate thrust loads in either direction along the rotor shaft. In most cases, oil is supplied through lubricating oil channels to lubrication wells in each pad of the bearing. The bearing is mounted to lands cast or machined within the center housing of the turbocharger using bolts or other conventional fasteners and the lubricating oil channels in the bearing engage oil supply sources in the center housing.
As turbocharger rotational speed and loads increase, the horseshoe bearing configuration may not provide sufficient thrust bearing capacity or unsymmetrical loads may be created due to the open portion of the bearing. 360xc2x0 bearings, however, may impose unacceptable assembly constraints in manufacturing the turbocharger if the shaft must be inserted through the bearing. It is, therefore, desirable to have a bearing which can be assembled over the shaft of the turbocharger while providing 360xc2x0 load carrying capability.
The inventive bearing comprises a 360xc2x0 double sided thrust bearing having a central shaft bore and formed from two oppositely oriented interlocking elements each having an open segment subtending a mating angle, a first side with a plurality of bearing pads and a second side with an elevated segment having at least one bearing pad, the elevated segment opposite the open segment and subtending the mating angle to be received within the open segment of the other interlocking element.
The bearing elements are assembled around the shaft interconnecting the turbine and compressor impellers of the turbocharger and received within the channel of a thrust collar mounted on or machined into the shaft, the channel walls engaging the bearing pads to react thrust forces along the shaft in either direction. Lubrication for the pads is provided by oil channels formed in the mating faces of the two elements with interconnecting orifices into the lubrication well at each pad. Oil channels for the pads in the elevated segment interconnect with the oil channels in the mating surfaces or alternatively comprise conduits from the shaft bore or dedicated inlet orifices on the bearing periphery.